Radiaror / Engine cooling, best fan set up

[Taily]

Keeping the pressure up on the coolant also increases the heat transfer rate between the cylinder walls and the coolant. Otherwise small bubbles would form on the hot metal internal surfaces, then (over time) displace coolant from the system.

Those bubbles are the same concept as boiling a kettle or billy on a fire or gas ring - as the metal kettle/billy etc starts to get warm, small air bubbles form where the heat transfer is taking place. With pressure on the system (ie; a functioning radiator cap) the formation of those air bubbles is (almost) eliminated. I've set my ute up with a 16psi recovery set up for the last 17 years without an issue apart from blowing a welch plug early on when I first set it up. That extra one psi (factory aircon car originally had a 15 psi non-recovery cap) was enough to finish that 25 year old plug off.

[wbute]

I reckon if you want a good system you shouldn't really cut the corner on a recovery bottle and higher psi cap. The bottle is a fairly important part of it.

[sandasharpe]

I'll try my hardest to add to your confusion. Taily is spot on. I don't think he spelled out that when the vapour bubbles form they slow down transfer of the heat (coolant transfers heat better than vapour).

As to whats better, viscous coupling or thermo fans? Generally on old tech go with the viscous coupling (BMW still use them). On old tech you can't engineer in the safety systems that kick in to protect your engine when thermo fans fail ie blown fuse, damaged wiring, worn parts etc. These failure modes are remote < than 1 in 1,000 but still. A viscous coupling gives plenty of warning before it fails and is more a slow degradation over time

Viscous couplings are noisier and less efficient (you won't notice the difference in efficiency its that small) but more robust. If robust is absolutely important then go for a fixed blade but they are much more inefficient.

[sandasharpe]

One more thing, electrolysis occurs through the coolant and will pick the most reactive metal and use it as a sacrificial anode. This is usually aluminium but not all aluminum is the same. They are alloyed differently depending on the casting process used and the temperatures and forces it will experience in service. The water inlet on Isuzu Gemini engines used to be super sensitive to this because of the type of alloy used.

The best protection is a top quality coolant / glycol. Mobil, penrite, valvoline, shell, make sure it is O.E. quality. I used to visit ACL gaskets when they were in business, and they would to test glycols for there affects. Some of them used to accelerate electrolysis!!!!

[Valencia]

I got rego (over the pits) with out overflow bottle in WA

Well thats a first

[damienengland]

An old Chamberlain we had with a John Deere engine it let go from it. Took about 9000 hours though. One sleeve was hammered in one spot. Looked like a sandblaster had been at it. Got another old Chamberlain that blows head gaskets because the sleeves have sunk down on the o-rings. I have replaced the head gasket twice now mainly because it's cheaper than rebuilding and machining the block to fix it.
Cooling systems are more of a "system" than is realised as you said. It should be fairly straight forward to get a V8 Holden right. I never saw too many issues with the Cat 793 trucks I drove at Cadia. They were 2700hp V16 operating in temps from below zero to over 40. Running out of the pit under full load for 30 minutes to get to the top! That was a real eye opener for me.

Attachment 13708

Great chart WB. I bet those 793's were running 3516 engines, they are the Cat success story, big cubic displacement, diesel fuel under high pressure and plenty of forced induction. Yummy!!!! I bet they sounded awesome at 2100rpm with full load and a steep incline. Having said that, we eventually got rid of all our 3516's as they were just too expensive to maintain on a cost per kW basis. That's when we went with the Cummins equivalent. Anyway, good chatting about high horsepower diesel engines for a bit.

[Spike]

Keeping the pressure up on the coolant also increases the heat transfer rate between the cylinder walls and the coolant. Otherwise small bubbles would form on the hot metal internal surfaces, then (over time) displace coolant from the system.

Those bubbles are the same concept as boiling a kettle or billy on a fire or gas ring - as the metal kettle/billy etc starts to get warm, small air bubbles form where the heat transfer is taking place. With pressure on the system (ie; a functioning radiator cap) the formation of those air bubbles is (almost) eliminated. I've set my ute up with a 16psi recovery set up for the last 17 years without an issue apart from blowing a welch plug early on when I first set it up. That extra one psi (factory aircon car originally had a 15 psi non-recovery cap) was enough to finish that 25 year old plug off.

All very interesting and great info. When I purchased my radiator I went to a radiator repair shop and asked the guy what the factory listed for the HX, he dragged out the book and it listed HX with and without recovery bottle and listed the same psi cap for both. I would have thought that the cap would be a little higher pressure rating without the recovery bottle. Taily what bottle do you use, mounted where and is the height of the bottle important?

[wbute]

Great chart WB. I bet those 793's were running 3516 engines, they are the Cat success story, big cubic displacement, diesel fuel under high pressure and plenty of forced induction. Yummy!!!! I bet they sounded awesome at 2100rpm with full load and a steep incline. Having said that, we eventually got rid of all our 3516's as they were just too expensive to maintain on a cost per kW basis. That's when we went with the Cummins equivalent. Anyway, good chatting about high horsepower diesel engines for a bit.

Yep everything is just huge on them. You could get heaps of info up on the dash. One thing was litres of fuel per hour. Coming out of the pit loaded with 250 tonnes they burnt 380 litres per hour! First time I pulled into the fuel bay and filled one up I was glad I wasn't paying. 3000 litres, for one shift of 12 hours. They ran 20 big trucks.
You can put the recovery bottle anywhere within reason. They work with pressure equalisation, not a syphon. I think they were screwed onto the radiator support on HX.

[Taily]

All very interesting and great info. When I purchased my radiator I went to a radiator repair shop and asked the guy what the factory listed for the HX, he dragged out the book and it listed HX with and without recovery bottle and listed the same psi cap for both. I would have thought that the cap would be a little higher pressure rating without the recovery bottle. Taily what bottle do you use, mounted where and is the height of the bottle important?

I used a fairly simple system. A 2.5lt Valvoline coolant bottle (doesn't matter what it is from, just the shape of the bottle) that I just sat in between the battery and the LH guard. I left the cap on the bottle but drilled a 9-10mm hole in the top, through which I loosly inserted a bit of 8mm (5/16) metal tube (long enough to touch the bottom of the bottle) with a bend where it emerged from the bottle. I attached a bit of clear hose between that and the radiator overflow outlet, with enough slack in the tube that I could slip the top off the bottle easily. As WBute mentioned, the installed height of the bottle isn't important, just that there is enough room in the bottle to accept the (temporarily) expended water from the cooling system and that the tube is deep enough in the bottle to allow the contents of the bottle to be completely drawn into the cooling system if need be.

Mine was only a basic set up but what it worked just as well as the factory set up on the later HX/Z/WB. I used a metal tube in the bottle as a rubber hose can kink and the system wont work. The advantages of doing this to your cooling system are threefold: you wont drop coolant everywhere everytime you stop somewhere; You wont have to physically remove the cap to check your coolant level, and; You wont have any air/oxygen in your cooling system to accellerate corrosion.

If I was going to re-make mine I'd use a clear bottle so I could more easily see the level of the overflow bottle - though you can now buy a repro HX on recovery bottle from Rares (etc). Not sure if it comes with a mount to the LH inner guard though...

[sandasharpe]

2 different mounting for recovery bottle - on the guard is generally HZ, on the battery tray next to radiator is option HJ/X, although its not that clear. Battery tray mounting could have been dealer fit? The one on the green van is mine, originally 253 4speed the other is a HX Monaro.XVQ5-Resized640x480.jpgHX-Monaro-GTS-005.jpg